Re: [GBlist] kitchen hood cfms

[John Salmen <terrain@shaw.ca>]

The HVI recommendations I thought were higher. A basic way of determining
the size would be to relate it to the room size and activities.  If you were
wanting to simply deal with cooking moisture something in the range of 8-10
air changes per hour would be in order - so a cooking area that measured
10x10x10 would need a fan capable of moving 8000 cubic feet of air in an
hour or about 130 cfm. If you wanted to quickly get rid of fumes or smoke in
the overall kitchen and not have it migrate to the rest of the house
(burning toast) you would want something more in the order of 15 air changes
per hour which would double the size or overall capacity of the fan. But a
range hood is typically not exhausting the whole kitchen so is basically
focused over the stove with some spillage area - the closer to the stove the
more effective.  To simply vent a kitchen during regular cooking of excess
moisture and some cooking fumes I would recommend a variable fan with a
lower range of about 150 or less and keeping to the lower ventilation range
for most activities with a top range of about 250 - and make sure that the
fan is designed to operate most efficiently and quietly at the lower range
rather than the higher. Typically this would mean a 6" duct - pressure drops
(from roof caps, elbows, etc) can reduce the effectiveness of a given fan
rating so you need to look at the kind of pressure a fan is rated at.
Typically they are rated at something called .1 wg (water guage)Ideally you
would find a fan rated at a certain cfm at .25 wg

I'm not a fantech guy so perhaps other people have more specific
recommendations about ACH needs in a kitchen.

John


----- Original Message -----
From: "Sacie H Lambertson" <dlambert@grasshoppernet.com>
To: <greenbuilding@crest.org>
Sent: Tuesday, October 30, 2001 12:28 PM
Subject: [GBlist] kitchen hood cfms


> Hmm, in my on-going monologue regarding the proper cfm fan for a kitchen
> hood, Fantech recommends twice the CFM as the Home Ventilating Institute
(a
> Canadian gp maybe?).  They suggest 100 cfm per lineal feet of stove.
> Comments?   SL
>
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______________________________________________________________________
This greenbuilding dialogue is sponsored by REPP/CREST, creator of
Solstice http://www.crest.org, and BuildingGreen, Inc., publisher of
Environmental Building News and GreenSpec http://www.BuildingGreen.com
______________________________________________________________________